A Systematic Review and Meta‐Analysis of The Effect of Low Vitamin D on Cognition

Abstract

Observational evidence demonstrates low vitamin D is related to poorer cognition; however, interventional studies are yet to show a clear benefit from vitamin D supplementation. From the evidence to date, there is likely a therapeutic age window relevant to the development of disease and therefore vitamin D therapy. Longitudinal lifespan studies are necessary to depict the optimal timing and duration in which repletion of vitamin D may protect against cognitive decline and dementia in aging, to better inform trials and practice towards a successful therapy.

Association of vitamin D and vitamin B12 with cognitive impairment in elderly aged 80 years or older: a cross‐sectional study

“…In the present study, we found an association between vitamin D levels of ≤18 ng mL À1 and a higher prevalence of cognitive decline. Similarly, a systematic review and meta-analysis developed by Goodwill and Szoeke (32) that included 26 observational studies found an association between low vitamin D levels (ranging from <25 to <50 nmol L À1 ) and worse cognitive performance. In their meta-analysis, Shen and Ji also found that subjects with vitamin D deficiency [25(OH)D levels <50 nmol L À1 ] were at increased risk of developing Alzheimer's disease compared to those with 25(OH)D levels of ≥50 nmol L À1 (33) .…”

Vitamin D‐mentia: Is Vitamin D Optional or Essential for Preventing Late‐Life Cognitive Decline?

“…Regarding domain‐specific cognitive abilities, mental speed and attention (summary OR = 1.23, P = .004) and visuospatial abilities (summary OR = 1.32, P = .03) had stronger associations with vitamin D than memory ( P = .19). Finally, vitamin D supplementation had no significant effect on cognition (standard mean difference = 0.21, 95% CI = −0.05–0.46) …”

“…This issue of the Journal of the American Geriatrics Society contains an elegant systematic review and metaanalysis by Goodwill and Szoeke aimed at quantitatively assessing the effect of low vitamin D or vitamin D supplementation on cognition in midlife and older adults without a diagnosis of dementia . Twenty‐six observational (12 cross‐sectional, 14 longitudinal) and three interventional studies were included in the metaanalysis (n = 19–9,556).…”

“…Some trials have included participants with relatively high serum vitamin D concentrations, possibly above the cerebral needs for vitamin D (if any), which could mask the cognitive effect of vitamin D supplementation . Moreover, comparative arms were allowed to continue receiving vitamin D supplements as part of routine care . Thus it will be important in the future to compare the cognitive effect of vitamin D supplements with that of placebo in populations exhibiting hypovitaminosis D at baseline.…”

Vitamin D deficiency is associated with reduced hippocampal volume and disrupted structural connectivity in patients with mild cognitive impairment

“…However, the mini-mental state examination (MMSE) has been the most commonly administered scale to assess the global cognitive functioning (Goodwill & Szoeke, 2017). However, the mini-mental state examination (MMSE) has been the most commonly administered scale to assess the global cognitive functioning (Goodwill & Szoeke, 2017).…”